Machine tool



J1me 29, 1954 ARMITAGE- 2,682,182

MACHINE TOOL Filed Oct. 21, 1950 13 ShetS- Sheet 1 g Mk4;

J/Q/mgy June 29, 1954 ARMlTAGE 2,682,182

MACHINE TOOL Filed Oct. 21, 1950 13 Sheets-Sheet 2 if MmM 16-- I AHOPiJey June 29, 1954 J. B. ARMITAGE 2,682,182

MACHINE TOOL Filed Oct. 21, 1950 13 Sheets-Sheet 3 June 29, 1954 J. B. ARMITAGE MACHINE TOOL l3 Shets-Sheet 5 Filed Oct. 21. 1950 June 29, 1954 .1. a. ARMITAGE 2,682,182

MACHINE TOOL Filed Oct. 21, 1950 13 Sheets-Sheet 6 INVENTOR.

ornez June 29, 1954 J ARMlTAGE 2,682,182

MACHINE TOOL Filed 061',- 21, 1950 13 Sheets-Sheet 7 IN V EN TOR.

c/argv 5 $1221? filo'rnel J1me 1954 J. B. ARMITAGE 2,532,182

MACHINE TOOL Filed Oct. 21, 1950 13 SheecS -Sheet 8 far/76y June 29, 1954 ARMlTAGE 2,582,182

MACHINE TOOL Filed Oct. 21, 1950 13 Sheets-Sheet 9 mam r [Ill/III,

IN V EN TOR.

, flzzome June 29, 1954 J. B ARMITAGE MACHINE TOOL 13 Sheets-Sheet 11 Filed Oct. 21, 1950 fn Vent a r ix'qvfi E 141 12211 4 mww QMN

June 29, 1954 J. B. ARMITAGE 2,682,182

MACHINE TOOL Filed Oct. 21, 1950 13 Sheets-Sheet 12 June 29, 1954 J. B. ARMITAGE MACHINE TOOL l3 Sheets-sheaf. l3

Filed Oct. 21, 1950 Invent 0 2- JZseh Z Armziaje E) Attorney Patented June 29, 1954 UNITED STATES ATEIN'T OFFICE MACHINE TOOL Joseph :B. Armitage, Wauwatosa, .Wis assignor to.-Kearney .& L'lrecker Corporation, West Allis, W is., a' corporation of Wisconsin Application .Dctober 21, 1950,:Se1ial No. 191,462

53 Claims.

"Another. objectof the inventionis.toprovide :an improved power transmitting mechanism .for

actuating movable elements of. a machine tool.

..-Another object is toprovideina machine tool, an. improved transmission mechanism 1 including fixed step andinfinitelyvariablespeed changing apparatus operating in combination.

.:.-Another object I is to, provide an improved selectively movable supporting headforthe. inde- 1 pendently .movable spindle icarrying quill .of a machine tool.

. Another object. is to provideian improved cooperative speed controlling and indicating eappa- :ratus for z.a...combined.fixed step. and. infinitely variable speed changing mechanism.

Another objectds. to provide an improved telescop'ingpower transmitting mechanism foractuating a .m'ovable' tool supporting member of J a machine tool.

J 'Another obj ect.is to; provide; an improved :-.-ar- 1. rangement'. for a adjusting the tension of :acdriving belt in a machine. tool power transmission mechanism.

"Another object .is 'to. provide an improved spindle supporting quill mechanism foralmach-ine tcol.

nnother objrectis to provide. an. improved comnbined powerlsource and variable speedtransmission mechanism arranged .to constitute a unitary driving apparatus for the movable elements of amachine tool.

Another. obj ecttis to. provide: improved .actuating and .controlling:cmechanism. for moving a machine tool operating member.

Another :objeet istoiprcvide an improved; drivmechanism fora machine tool that comprises a resilient drive, .an infinitely variable :speed changer in combinationwvith a fixedwstep. range changer, and a second resilient driveinterconheated in series between a powertsource and .a tool spindle in manner to absorb .shockloads in transmitting power therebetween and fordriving the tool spindle with a minimum of vibration during a cuttingoperation.

*Another object 'is'to provide anzimproved com- -==bined s-peed-indicating andvcontrolling.apparatus:

v2 forv selectively-adjusting the variable speed transmission mechanism of a-machine tool.

Another object-is to. provide an improved selfaligningelevating mechanism for effecting selective adjustment of a movable member of a machine tool.

Another object is to provide an improved .mounting arrangement for -.a unitary main driving mechanism for a machine tool that is-espe- .ciallyadaptedto provide convenient access to the constituent units comprisingthe mechanism in .the event it isnecessary to inspect or adjust one oranother of the units.

A further object is to provide improved locking means and. clamping 'mechanism for retaining movable members of a machine tool in desired position.

A further object is to provide an improved chip .receivingarrangement for a machine tool.

Astillfurther object is to provide improved precisionpositioning apparatus for a movable element of a machine tool.

According to this invention, a precision boring machine of the vertical spindle type is provided with improved supporting and driving mechanism, including speedchanging apparatus constituted by a fixed step'gear shifting mechanism and aninfinitely variable belt drive mechanism functioning cooperatively under the controlof a unitary speed adjusting and indicating device.

Power is transmitted from the fixed step mechanism to the vertical spindle by belts and pulleys,

the fixed step mechanism being movably mounted in the machine frame to provide for adjustment of the spindle driving belts. The speed adjusting and indicating device isv connected to the speedchanging apparatusby control linkage arranged to accommodate movement of the transmission and to provide for movement of the expansible pulleys of the infinitely variable belt drive. The tool spindle is journalled in an improved axially adjustable hollow quill into which a driving shaftextends from the pulley and has splined connection with a portion of the spindle.

Feeding -movement -of-the spindle is effected through rate changing -mechanism driven by means of an extensible connection from the movable spindle driving-transmission mechanism. A

separate motor is provided for effectingrapid traverse .movement, the motor. being controlled by a;push button :onwthe, reversing lever. l, An improved multiplemstop and position indicating apparatus -.-is provided 1 for controlling precise The spindle tion of an improved clamping device. Improved clamps are likewise provided for holding the saddle and table, these elements being adjustable by means of improved precision screw and nut actuating and indicating apparatus.

In a modified form of the invention, there is provided an improved supporting head disposed to be mounted for selective vertical adjustment on the upper forward face of a machine column, and arranged, in turn, to slidably support a spindle carrying quill for independent selective axial adjustment. For driving the tool spindle at a selected rate of speed, as well as for effecting selective power driven movement of the axially movable quill at a proportionate feeding rate, there is provided an improved combined unitary power source and infinitely adjustable speed changing transmission mechanism removably mounted within the hollow base of the machine. In order that the spindle quill may be operated with the utmost accuracy as a cutter is advanced toward a workpiece in performing a metal cutting operation, an improved elevating apparatus comprising a self-aligning screw and nut mechanism is operatively connected to effect selective axial movement of the quill within its supporting head.

In each embodiment of the invention, the spindle driving transmission mechanism is particularly adapted to drive the tool spindle with a minimum of vibration as well as to afford protection to the speed changing mechanism in the event of sudden shock loads that might be imposed by complete, even though momentary, cessation in the rotation of the tool spindle. To this end, one resilient power transmitting driving connection is interposed between the driving motor and the speed changing mechanism, and a second resilient driving connection is interposed between the speed changing mechanism and the tool spindle for the primary purpose of minimizing vibration and cushioning the entire power transmitting mechanism against sudden shock loads.

Ihe foregoing and other objects of this invention will become more fully apparent upon consideration of the manner in which they may be achieved by means of the exemplary apparatus illustrated in and hereinafter described in connection with the accompanying drawings, in which:

Figure 1 is a view in front elevation of a vertical spindle, precision boring machine embodying some of the principal features of the present invention;

Fig. 2 is a view in right side elevation of the boring machine shown in Fig, 1;

Fig. 3 is a view in vertical section through the column of the machine, taken on the plane represented by the line 3-3 in Fig. 2;

Fig. 4 is an enlarged view in vertical section through the head and the upper part of the column of the machine, taken on the plane represented by the line 44 in Fig. l

Fig. 5 is a horizontal sectional view through the spindle head, taken on the plane represented by the lines 55 in Figs. 1, 2 and 4;

Fig. 6 is another view in horizontal section through the spindle head, taken on the plane represented by the lines 6-6 in Figs. 1, 2 and 4;

Fig. '7 is a view in right side elevation of a modified form of a vertical spindle, precision boring machine with the lower portion of the column and base broken away to show an improved combined power source and variable speed 4 transmission mechanism, taken along the line 1--1 of Fig. 11;

Fig. 8 is an enlarged view in vertical section through the vertically movable spindle head and the upper part of the supporting column of the modified form of boring machine shown in Fig. '7

Fig. 9 is a fragmentary view in horizontal section through the self-aligning elevating screw nut and its cooperating elevating screw, taken along the line 9-9 in Fig. 8;

Fig. 10 is a fragmentary plan view of the column and the relatively movable spindle supporting head of the modified form of boring machine, taken partly in horizontal section through the cooperative guiding ways along the line l0-HI of Fig. '7;

Fig. 11 is a view partly in front elevation, partly in transverse vertical section through the upper portion of the column, and, partly in vertical section through the base of the modified form of boring machine, taken along the line ll-H of Fig. "I;

Fig. 12 is an enlarged schematic View of a modified form of infinitely variable speed changing transmission mechanism together with the speed indicating and controlling apparatus therefor;

Fig. 13 is a view in vertical section through a modified form of range changing transmission mechanism, taken along the line (3-4 3 in Fig. 14

Fig. 14 is a view in vertical section through the base of a modified form of the precision boring machine and showing a further modified form of combined unitary power source and variable speed transmission mechanism;

Fig. 15 is an enlarged vertical sectional view through the table, taken on the plane represented by the line i5l5 in Fig. 1;

Fig. 16 is a view in vertical section through the machine bed and work supporting table, taken substantially on the plane represented by the line IE-l6 in Fig. 2;

Fig. 17 is an enlarged fragmentary view of the spindle stop mechanism on the right side of the spindle head, as shown in Fig. 2;

Fig. 18 is a detail view of the stop mechanism in horizontal section, taken on the plane represented by the line I8--! 8 in Fig. 17

Fig. 19 is another detail view in horizontal section, taken on the plane represented by the line [9-19 in Fig. 17; and

Fig. 20 is a further detail view in horizontal section, taken on the plane represented by the line 2020 in Fig. 17.

The particular machine tool herein set forth to illustrate a practical embodiment of the various features of this invention, is a precision jig boring machine of the vertical spindle type.

Referring more specifically to the drawing and particularly to Figs. 1 and 2 thereof, the boring machine comprises essentially a hollow base or bed 20 carrying an integrally formed upstanding hollow column 2|, the combined structure constituting the frame of the machine and the housing for the driving mechanism. As shown. the base 20 projects forwardly from the column 2| and has slidably mounted on its upper surface a saddle 22 that carries a movable work supporting table 23, the arrangement being such that the saddle may be moved toward or from the column and the table moved along the saddle at right angles to its path of movement.

At its upper end, the column 2| is provided with a forwardly projecting spindle head 25 that overlies the base 20 and carries a vertically positioned trains toolspindle 2,6 in cooperating relationship with the WQltk supporting table 23. g V I Ajs best shown in Figs. 4, 5 and 6, the tool spindle, 26 is rotatably mounted in a spindle quill 2'1 thatis slidably mounted in the spindle head 25 for axialmovement therein to effect feeding of a cutterfiil carriedby the spindle relative toa Workpiece that may be mounted on the table 23. e The quill 21 is essentially a hollow cylindrical member fitted in a complementary bore in the head 25 and provided with a, longitudinal keyway 3 I which engages akey 32 fixed in the head to prevent the quill from turning. The spindle 2B is journalled inthelower portion of the quill in a pair of antifriction bearings, of which the upper bearing 33 is shgwn, which are separated by a spacing memher 35. Above the upper bearing 33, the spindle presents a splined portion 35 of reduced diameter that cooperates with an internally splined hollow shaft 31 projecting downwardly from the upper Dartof the head into the hollow quill.

As'shown in Fig. 4, the hollow shaft 31 is rotatably mounted at its upper end in the spindle head bymeans, of a bearing 38, above which the shaft is fitted with a combined driving belt pulley and flywheel 39. The lower end of the hollow shaft 311s supported by a bearing M, which fits within the hollow quill 2! and has vertically slidable engagement therewith to provide for relative axial movement, the arrangement being such that the quill 21 and the spindle 26 may have vertical movement relative to the head 25 and the hollow ,driving shaft 3?, without interfering with the driving connection and without requiring that any part of the spindle extend above the driving pulley 39. By this arrangement, driving torque is transmitted by the relatively rigid hollow shaft 3'! to a point as near as possible to the tool receiving nose of the spindle. A special arrangement for lubricating the spindle and quill and for withdrawing excess lubricant from the region of the lower spindle bearing is set forth in copending application, Serial No. 579,459, filed February 23, 1945, now Patent No. 2,457,893, granted January Power for driving the spindle 26 and for effectingvertical feeding movement of the quill 21 ,is derived from an electric motor 5| within the hollow base 2 5 of the machine, as

mounted shown in Fig. 16. From the motor 5!, power is transmitted through an infinitely variable belt drive speed changing mechanism 52, as shown in Figs. 3 and 4, to a fixed step range changing mechanism 53 within the upper part of the column 2 l. The fixed step mechanism 53 is of the shiftable gear type and is provided with a belt driven pulley :54 disposed in driving relationship with the pulley 39 on the spindle 26.

A pair of belts 55 operatively interconnect the two pulleys for transmitting power at selected speeds to drive the tool spindle As shown in Figs. 3 and 4, the mechanism 53 is slidably mounted upon a pair of horizontal supporting guide rods 56 and El, disposed in parallelism with the belts 55 in the upper part of the column.

ll'or moving the transmission mechanism 53 along the rods to adjust the belts, there is provided a belt adjusting screw 58 that is rotatably mounted in the rear wall of the column 21 and has nism" 53. ,nected, through bevel gearing 82 within the Y ,ameters,

threadedengagement with a portion of a housing 59 that encloses the mechanism 53, the screw 58 being provided at its outer end with a squared portion for receiving an actuating instrument. By this arrangement, the belts 55 may be tightened by turning the screw 58 in direction to move the mechanismtB rearwardly along thesupporting rodslfit" and El. 7

h best shown in Fig. 3, the infinitely variable speed changing transmission mechanism 52 earnprises two expansible pulleysiii and "t2 interconnected for rotation as a unit and carried (in a movably mounted shaft '63. The expansible pulley iii is engaged by a beltt l, which also'kiooperates with and is driven by a rigid pulley t5 on theshaf t of the driving motor 5| (see Fig. 16). The other expansible pulley 82 receives a beltli'fi,

which also operates over a rigid pulley Bl carried by and connected to drive the fixed step range changing mechanism 53. The two expaiisibl'e pulleysti and'62 of the speed changer '52 may be expanded and contracted alternately through action of the cooperating belts up'on bodily movement of the pulley carrying shaft 63 toward or from the one or the other of the rigid pulleys 65 and El, respectively. For example, with the shaft 63 in the upper position, shown in the drawing, the pulleytl operates at a relatively small pitch diameter, while the pulley (32 operates adjustable control rod H, which extends upward and is connected at its upper end to the end of a crank arm 72 that is mounted on a protruding rocking shaft '13 at the side of a speed control box M fitted in the right side of the column 2!, as shown in Fig. 3.

Another crank arm l5, mounted on the rocking shaft 13 within the control box it, engages a traveling nut if that threaded engagement with a control screw shaft ll. The control shaft "ll extends longitudinally throughthe box i4 and projects from it at the right side of the machine. As shown in Figs. 2 and 3, the control shaft I? is provided on its exposed outer end with a control crank handle it, by means of which it may be rotated. When the handle "it is turned, the threaded shaft causes 1ongitudinal movement of the nut 2'8 which, in turn, causes rocking movement of the crank arms 75 andl2, to raise or lower the variable belt drive mechanism shaft 83, thereby varying the driving ratio by infinitesimal steps, as may be required to obtain the desired spindle speed.

H The pulley t7, driven by the belt 36 from the I infinitely variablespeed mechanism 52, is carried on the outer end of a shaft 8!, journalled in the housing 59 of the fixed step transmission mecha- As shown in l, the shaft Si is conhousing 59, to drive a vertically disposed primary shaft 83 of the fixed step mechansim. The shaft gtf has fixed to it, within the housing 59, three gear wheelsil l, 85 and B6 of different dior, driving a parallel secondary shaft 88 atone of three selected speedra'tios.

As shown, the secondary shaft 88 projects upwardly from the casing 59 and carries on its exposed upper end the spindled driving belt pulley 54. Within the casing 59, the shaft 88 has splined connection with a gear couplet 9I, comprising gears 92 and 93, complementary to and adapted to mesh selectively with the gears 84 and 85, respectively, on shaft 83, to effect either of two driving ratios. A third gear 94 is rotatably mounted on the shaft 88 in constant meshing relationship with the third gear 85 on the primary shaft '83, the couplet 9| being provided with jaw clutch teeth 95 for engaging complementary teeth on the hub of the gear 94 to effect a selective driving comiection between it and the shaft 88 for effecting the third driving ratio when both the gears 92 and 93 are out of mesh with their respective driving gears.

For positioning the gear couplet to select the desired fixed step speed ratio, the couplet is engaged by a shifting yoke 91 mounted on the upper end of a vertically disposed shifting rod 98, ash shown in Fig. 3. The lower end of the rod 90 is operatively connected by a tongue and groove sliding connector 53 with the upper end of an actuating shaft I05, which projects upwardly from the control box 14, the arrangement being such that vertical movement may be transmitted from the shaft I00 to the shaft 98, regardless of horizontal movement of the fixed step mechanism 53 in adjusting the tension of the driving belts 55.

Within the control box I l, the shaft I00 is connected with a pivotally mounted actuating arm IOI carrying a cam follower 252, which engages a cam groove in a cam plate I03, rotatably mounted concentric with the control shaft 11. As shown, the cam plate 803 is fixed to a sleeve I04 that projects from the side of the machine and carries on its outer end a speed indicating dial plate I and an actuating crank handle I06, The crank handle I023 is fitted with a latching pin I01 which, when withdrawn from a cooperating latching opening in the face of the box 14, permits the crank and the dial I05 to be turned to a new position in which another latching opening is engaged by the pin I01. This results in turning the cam plate E03 and effecting vertical movement of the actuating rod H and the shifting rod 98 to shift the gear couplet SI for effecting a different driving connection between the shafts 83 and 88.

Three latching openings are provided for positioning the indicating dial I05 in the three positions corresponding with the three fixed step speed ratio positions of the gear couplet 9|, a fourth latching opening being provided for latching the dial with the couplet SI in a neutral position, such as shown in Fig. 4, in which the gears 92 and 93 and the clutch teeth 95 are all out of mesh with their cooperating driving members.

For indicating the speed of the spindle 26, the dial I05 carries speed indicia divided into three segments corresponding, respectively, with the speed ranges provided by the three gear ratios of the fixed step driving mechanism 53. For indi cating the speed on the dial I05, there is provided a speed pointer I69, which ranges over the active segment of the dial in accordance with the setting of the infinitely variable belt drive mechanism 52. As shown in Fig. 3, the pointer I09 is carried on the outer end of a sleeve I I I, disposed to rotate within the hollow sleeve I04 of the dial I05 and concentrically with the screw shaft 11.

8 The sleeve III is provided with an inwardly projecting cam follower II2, which engages a spiral cam groove II3 formed in a sleeve II4 directly connected to be rotated by the traveling nut 18. As is readily apparent, when the speed adjusting crank 18 is turned to move the nut 16 along the screw 11 in adjusting the infinitely variable speed changing mechanism 52, the cam groove II3 operates upon the cam follower II2, fixed on the sleeve III, in manner to cause the sleeve and the associated pointer I09, to rotate relative to the box 14. By this arrangement, the pointer m9 is caused to turn in accordance with adjustment of the variable speed belt driving mechanism 52 and cooperates with the active segment of the dial I05 corresponding with the fixed step ratio established by adjustment of the transmission mechanism 53 through positioning of the range change actuating crank I06.

The spindle carrying quill 21 is arranged for vertical feeding movement either manually or by power through operation of a vertically disposed feed screw I2I that is rotatably mounted in the head 25 in parallel relationship with the quill, as best shown in Fig. 4. The screw I2I cooperates with a nut I22 that is carried by a cap I23 fastened to the upper end of the quill 21. Power operation of the screw I2I in selected direction is effected by means of a reversing mechanism, including a pair of opposed bevel gears I24 and IE5 mounted for rotation concentrically with the screw and both having meshing engagement with an interconnecting driving bevel gear I25 mounted on a horizontal stub shaft I21 journalled in the head 25. The reversing gears I24 and I25 may be coupled to the screw IZI selectively by means of a shiftable clutch collar I28 that is slidably splined on the screw shaft between the gears for movement into engagement with either of them. To facilitate movement of the quill 21, its weight is counterbalanced by means of a counterweight E31 that is suspended within the hollow column 2! by a chain I32, which operates over idler sprockets I33 and I34 in the upper part of the column and head, and is connected to the quill cap I23 in manner to exert force upwardly upon it to counterbalance the weight of the quill and spindle.

Shifting of the clutch collar I28 is effected by operating a feed lever I36 mounted on the right side of the head 25 on the protruding end of a shaft I31 journalled transversely of the head, as shown in Fig. 6. The shaft I31 carries a gear segment I30, which meshes with a complementary gear segment I39 on a reversing yoke I40 that is pivotally mounted in the head parallel with the shaft I31 in position to engage and operate the reversing clutch collar I28, the arrangement being such that, when the lever I35 is pivoted upward or downward, it moves the clutch collar in manner to effect power driven movement of the quill 21 in corresponding direction.

Movement of the quill by power at rapid traverse rate is effected through operation of a separate motor I42 mounted horizontally in the head 25 (as shown in Figs. 4 and 6) and provided with a pinion I43, which meshes with a gear I44 that is connected to the stub shaft I21 by means of an overload release or safety clutch I45. For energizing the motor I42 to effect rapid traverse movement, the reversing feed lever I36 is provided at its outer enlarged end with a push button I46, which operates mechanical linkage extending through the lever I35 and the shaft I31 to move an actuating element I41 Projecting from the end of the shaft I31. in manner to operate upon a switch plunger i 43 for closing a switch M that is electrically connected in well known manher to efiect energization of the motor I 42.

Power feeding movement of the quill 2? at selected feed rate is effected by operation of a feed rate selecting gear changing mechanism I5I mounted in the head 25 and operating through an overrunning clutch 5522 to drive a gear I53, which meshes with the gear l l i on the stub shaft I27 connected with the reversing mechanism. Power is transmitted to the rate changing mechanism I5I through an input gear lM, which has meshing engagement with a relatively long pinion I55 driven by the fixed step range changing mechanism 53. As best shown in Fig. 4, the long pinion I55 is mounted on the extended end of a shaft I56 journalled in a projecting portion of the speed changer housing 59, the arrangement being such that when the housing is moved to adjust the tension in the belts 55, the long pinion I55 slides longitudinally relative to the input gear I54, while maintaining driving connection with it. At its other end, the shaft IE6 is provided with a worm wheel I51 that meshes with and is driven by a worm I58 on the lower end of the secondary shaft 88 of the fixed step speed changer.

Adjustment of the rate changing mechanism I5I is effected in well known manner by operation of a rate changing and indicating mechanism IG I mounted on the right side of the head 25, as shown in Fig. 2. Since the rate changer I5I is driven by the secondary shaft 68, which also drives the spindle 26, the rate of feeding movement effected by the rate changer is directly proportional to the speed of rotation of the spindle 2B.

When the machine is in operation, the desired spindle speed and rate of feeding movement are established by the respective adjusting and indicating mechanisms and the direction of feeding movement is selected. by moving the feed lever I36 up or down to engage one or the other of the gears I24 and I25 of the reversing mechanism. Since the rate changing mechanism ISI drives the reverse mechanism through the overrunning clutch 552, if it is desired to move the quill 2i rapidly while the feed is engaged, to advance the cutter 28 to the work, for example, it is merely necessary to depress the rapid traverse button I46 on the feed lever to energize the motor I 42 for driving the stub shaft I21 and reverser at rapid rate with the clutch I 52. overrunning. When the quill 2? has been moved a sufiicient distance at rapid traverse rate, the button I iii may be released to deenergize the motor Hi2, whereupon the rate changer liiI will again pick up the driving action through the overrunning clutch M2 to resume feeding movement in the same direction, incidentally turning the shaft of the motor I 42 at moderate speed. Movement of the quill 2? may be effected manually through actuation of a feed hand wheel I65 mounted on the right side of the head 2 as shown in Figs. 1, 2, 5 and 6. Referring now to 5, the hand wheel. M35 is carried on the outer end of a horizontal shaft its journalled in the head 25 and that has fixed to its inner end a bevel pinion lii'i, which meshes with a comple'mentary bevel pinion 968 on the lower end 'of'the feed screw ifl, as shown in Fig. 4. The hand wheel IE5 is rotatably and slidably mounted on'the shaft its and is provided with positive clutch teeth I85, which effect a driving connection with complementary teeth on a collar I'Iii keyed to the shaft when the wheel is in its inner position. I

In order to avoid the possibility of the hand wheel I65 being rotated by power, an interlocking arrangement is provided, including a springpressed plunger Ill that is adapted to engage a conically shaped recess 572 in the side face of the gear segment 138 when the feeding lever 236 is in the neutral position. When the lever I536 is shifted either up or down to move the reversing clutch collar I2}; into engagement with one or the other of the reversing bevel gears Hit or E25, however, the recess I'i2' is moved out of alignment with the rod i'II in such manner that the rod ITI is forced outwardly, as seen in Fig. 5, and through action of a yoke I13 thereon which engages an annular groove in the hub of the wheel I65, moves'the wheel outwardly to disengage the positive'clutch Ifiii and release the wheel from driving connection with the shaft I56.

To facilitate moving the spindle quill 2? to a predetermined position, suitable tripping and indicating mechanism is provided on the right side of the spindle head,as shown in the drawings and more particularly in the enlarged view, Fig. I'i. As there shown, a trip rod H5 is disposed vertically along the outer surface of the spindle head 25 and'is positively connected within the head to the quillc'ap I23 for vertical movement in parallel relationship with the quill 21. The trip rod I15 is provided at its lower end with a tripping lug I'iii that is adapted to engage either an upper trip dog IT! or a lowertrip dog I'Eii, both of which are adjustably mounted on a tripping bar I19 that is slidably mounted on the side of the head 25, parallel with the tripping rod Hi5. As appears in Figs. '6, l7 and l9,the tripping bar I79 is operatively connected by a tripping shoe I36 to the reversing yoke Hill and functions when either the stop dog IT! or the'stop dog I78 is engaged by the lug I16 to pivot the reversing yoke I 40 indirection to move the reversing clutch I28 to neutral position' "In operating the machine, the stop dogs Ill and I'IBmay be positionedas desired to funcion a's'limit' stops to prevent excessive feeding movement of the quill 27 in either direction. To provide for downward feeding movement of the quill 'to precisely predetermined selected positions, the machine is fitted with a precision fourposition stop mechanism I33. As shown in Figs. 17, '18 and 19, thefour-position stop mechanism comprises four threaded rods Hid disposed in parallelism with the tripping rod lit and mountedat their upper ends in a rotatable barrel I journalled in the head and at their lower ends in a generally similar rotatable barrel Iiii, likewise journall'ed in the head, the arrangement being such that the barrels may be rotated to bring any one of thefour rods into operating relationship with the tripping rod I75. A springpressed detent mechanism I 81, associated with the upper barrel I85, as shown in Fig. 18, operates to holdthe stop mechanism I83 in any one of four rotatably adjusted operating positions or in any one of four intermediate inactive positions.

Each of the threaded rods I84 is provided with a stop nut I88 thatmaybe locked in adjusted position at any point along the length of the rod for engagement by a cooperating abutment I89 at the'lower end of the tripping rod Ilii, a in dicated in Figs. 1'? and 19. If it is desired to machine four surfaces at different precisely predetermined elevations on a workpiece for em ample, the four stop nuts I88 may be predeterminately adjusted alon their respective screws I24 in manner to cooperate with the abutment I89 on the trip rod I15 for effecting a sequential positioning of the spindle at the required four vertically adjusted positions, respectively. The entire unit I33 may then be turned step by step to bring the several stop nuts I88 into operating position successively. When the spindle quill 21 is being fed downwardly by power to machine one of the surfaces of a workpiece at the predetermined level, the abutment I89 carried by the trip rod I15 is moved downwardly into engagement with whichever one of the stop nuts I88, that happens to be in the operating position. Further downward movement of the quill 21 then operates to move the entire stop mechanism I83 downward, causing the lower barrel I36 to exert force upon a trip yoke I9I, which is connected to the lower end of the trip bar I13 and operates to move it downward to disengage the reversingclutch I28, as previously explained, thereby discontinuing the power feeding movement of the quill Z1. Precise final positioning of the spindle quill may then be effected by continuing the downward movement through operation of the hand wheel I95, the lower barrel I83 of the stop mechanism 133, meanwhile, moving downward into engagement with the actuating plunger of a precision indicating instrument I93 mounted on the head beneath the barrel. The downward movement may be continued until the indicating instrument 93 indicates arrival of the quill 21 at the precisely determined position. Positioning for the next succeeding cut is then effected by moving the quill 21 upward, which ma be done at rapid traverse rate, as previously explained, then turning the stop mechanism N33 to bring the next succeeding one of the stop nuts I88 into operating relationship with the rod I15, whereupon the quill may again be fed downward until stopped and positioned, as previously explained. When it is not desired to use the four-position stop mechanism, it may be turned to one of the intermediate positions in which none of the stop nuts I98 are in operatively aligned relationship with the abutment I89 carried toward the lower portion of the trip rod I15.

The quill 21 is retained in the head 25 by a quill cap I95 secured to the forward face of the head by cap screws. For rigidly clamping the quill 21 in a selected position of vertical adjustment, the quill cap Hi may be drawn tightl against the quill. As shown in Fig. 6, some of the head retaining cap screws engage clamping blocks I95 slidably mounted in the head and presenting apertures which receive tapered clamping plugs I91, that are threaded in the side of the head. As appears in Figs. 1 and 6, there are two clamping plugs spaced vertically on the left side of the head, the upper plug being provided with a clamping lever I93 and the lower plug being connected to the lever by linkage I99. The arrangement of the clamping mechanism is such that when the lever I98 is pulled downward, both of the plugs are screwed into the head and their tapered ends act upon the apertures in the blocks I95 to draw the quill cap I95 into clamping engagement with the quill 21.

For holding the spindle 2E stationary to facilitate mounting or dismounting a tool in the spindle, there is provided a spindle locking arrangement, best shown in Fig. 4. A there shown, a vertically disposed locking plunger I is mounted for vertical sliding movement in the head in such manner that its upper end may engage locking recess-es 292 in the bottom face of the flywheel integrally formed with the pulley 39 secured to the upper end of the spindle driving shaft 31. An actuating lever 293 pivotally mounted on the front of the head 25 operates through an eccentric mechanism to move the locking plunger 29l up or down for looking or unlocking the tool spindle 26, as required.

A best shown in Figs. 15 and 15, the saddle 22 is slidably mounted on the bed 20 by means of spaced lways 2H and the table 23 is similarly mounted on the saddle by V-ways 2I2. The work supporting table may be adjustably positioned along the ways 2 I2 upon the saddle 22 by means of a precision screw 2I3, which is journalled in the saddle end and has threaded engagement with an adjustable nut 2M mounted in the table, the arrangement being such that lost motion is reduced to a minimum. A crank fitted hand wheel 2I5 is fixed on the end of the screw M3 for turning it in the usual manner.

As shown in Fig. 15, the saddle 22 is similarly adjusted relative to the bed 20 along the ways 21 I by means of a precision screw 2I1 rotatably mounted in the bed and having threaded engagement with an adjustable nut 2 [8 on the saddle. A crank fitted hand wheel 2I9 is secured to the outer end of the screw 2| 1 for rotating it. A position indicating dial 22I is adjustably associated with the hand wheel 2I9, to which it may be clamped in adjusted position by tightening a retaining T-bolt 222 that cooperates with an annular T-slot 223 in the dial. A counting mechanism 225 is associated with each of the screws 2l3 and M1, being driven by a gear train 226 operatively connected for actuation by the corresponding hand wheel. The arrangement of the counting mechanism and gear train is such that the counting mechanism 225 cooperates with the dial 22! to indicate precisely the position of the movable member through operation of the screw and nut, the action being generally similar to that of a micrometer. moving screw 2 I 1 and the table moving screw 2I3 are provided with counter and dial position indicating mechanisms, a work-piece on the table 23 may be adjusted relative to the cutting tool 28 in the spindle 26 to any position within the range of the machine with a high degree of precision through direct readings of the dial and counter combination.

After the table 23 has been precisely positioned,

it may be clamped to the saddle 22 by actuating a clamping lever 228. As shown in Fig. 15, the lever 228 serves to rotate a shaft 229 having spaced threaded portions which cooperate with a pair of slidably mounted nuts 230. When the lever is moved to clamping position, the nuts are drawn toward each other, causing inclined portions thereof to engage rollers on the upper ends of clamping plungers 23] which, in turn, operate to exert equalized force upon pivotally mounted clamping arms 232, which exert clamp- Since both the saddle upper ends of clamping plungers 24 l, which actuate pivotally mounted clamping arms 242 that engage the under sides of the ways 2| I, which support the saddle on the bed 20. Each of the positioning screws 2l3 and 211 is protected by a semi-cylindrical guard member 245, which prevents chips or other foreign matter from falling on the screw.

The chips which result from a machining op eration fall from the table and saddle into an inwardly sloping chip trough 241 formed on the upper part of the bed 20. As best shown in Fig. 16, the chip trough terminates in a central opening 248, through which the chips descend into a chip receiving pan or container 249 removably positioned within the bed 20 beneath the opening. To dispose of accumulated chips, the pan 249 may be removed from the machine bed upon opening a door 250 at the front of the machine.

In a modified form of the invention, as shown in Figs. '7 and 11, there is provided a boring machine having a hollow base or bed 255 integrally formed with a vertically upstanding hollow column 256 that is arranged to slidably support on its upper forward face a vertically movable spindle supporting head 251. The spindle head 257 projects forwardly from the column 256 in manner to overlie the work supporting table 23 and the saddle 22 that are slidably superimposed on the upper surface of the forwardly extending bed 255 for individual selective movement in mutually transverse horizontal planes. The head 25? is provided with a vertically bored hole arranged to slidably support the spindle carrying quill 21 for selective axial movement in parallelism with and independently of the vertical movement of the head along the column 256. An improved combined unitary power source and variable speed transmission mechanism 259 removably mounted within the rearward portion of the hollow base 255 of the machine is operatively connected to drive the tool spindle 26 journalled in the quill 21, as Well as to effect vertical feeding movement of the quill at a selected feeding rate directly proportional to the speed of rotation of the spindle. To more conveniently accommodate different sizes of workpieces and to achieve maximum accuracy in performing a metal cutting operation, there are respectively provided improved elevating means for effecting a selective vertical adjustment of the spindle head 25'! and clamping means for immovably securing the head to the column 266 in a selected position of vertical adjustment.

A principal advantage afforded by mounting the spindle head 25'! for independent vertical adjustment, as shown in Fig. '7, is the fact that the throat distance 260 formed between the top surface of the table 23 and the under side of the head may be selectively varied to accommodate different sizes of workpieces within the overall operating range of the machine. Thus, with the quill 21 in retracted position, as shown in the drawing, the spindle head 25? may be so positioned that a cutting tool 26| carried by the spindle 26 will just clear the top surface of a workpiece, for example the workpiece 262 mounted on the table 23. This arrangement is particularly advantageous in reducing to a minimum the unsupported length of the quill 21 that will project downwardly from the head 25'! as the cutter is fed downwardly in performing a drilling, boring, or a thread cutting operation on a workpiece. By minimizing the unsupported length of the quill 2'! extending below the spindle head 251, the quill is more rigidly supported to increase the accuracy with which the spindle 26 may be operated in performing any desired machining operation.

To guide the spindle supporting head 25's for vertical movement, as shown in Fig. 10, there are provided toward the upper front edges of the column 256 a pair of vertically spaced forwardly projecting square guideways 264 and 265, having flat front guiding surfaces 266 and 26! lying in the same vertical plane and inner diametrically opposed guiding surfaces 268 and 269 respectively contiguous to the front surfaces and positioned at an angle of ninety degrees thereto. A pair of generally complementary square way surfaces 212 and T3 formed in spaced parallelism toward the opposite rearward edges of the spindle head 251 are disposed to be slidably received by the respective square way surfaces of the column, a tapered gib 214 being adjustably secured to the leftward way surface 272 of the head for maintaining the proper slidable engagement between the way surfaces of the head 25? and the complementary guiding surfaces of the column 256.

To retain the spindle head 25'! in guiding relationship with the square way surfaces 264 and 265 of the column, a pair of vertical T-slots 215 and 2'16 formed toward the outer edges of the column 256 and extending inwardly from the front way surfaces 265 and 267 respectively, are adapted to be slidably engaged by a plurality of clamping T bolts 2'78. Each one of the clamping T-bolts 21!; extends forwardly through one of a plurality of spaced holes, respectively formed in a pair of laterally extending flanges 286 and 2%! integrally formed with the spindle head 25? at the opposite rearward sides thereof, in manner to be threadedly engaged by a respective one of a plurality of clamping nuts 262. Thus, the clamping T-bolts 218 are retained in engagement with the column T-slots 2'55 and 216 regardless of the vertically adjusted position of the spindle head 251 along the upper front face of the column 258. By means of this arrangement, the spindle head 25? may be clamped to the column 256 by selectively actuating the clamping nuts 282 which are operative in conjunction with the respectively cooperating T-bolts 278 to effect an equalized clamping action and thus minimize deflection in manner that vertical feeding movement of the quill 2? may be accomplished along a line of travel that is exactly perpendicular to the top surface of the table and parallel to the normal vertical path of travel of the spindle head 25?.

To effect a selective vertical adjustment of the spindle head 25?, as shown in Fig. 8, there is provided in the upper forward portion of the machine, a vertically disposed elevating screw 224- secured at its upper end to a forwardly extending cap 235 affixed to the top portion of the column 255 in manner that its forwardly projecting front portion will overlie the spindle head 25?. The elevating screw 286 extends downwardly through a suitable opening provided in the top surface of the spindle head 25'! in manner to engage with its lower threaded end a rotatable elevating screw nut 236 that is journalled to rotate in bearings 28'. and 283 carried by a transverse horizontal web 235) integrally formed with the housing for the spindle head. At its lower end, the rotatable elevatin screw nut 28% is provided with an integrally formed bevel gear 2% adapted to be engaged by a cooperating bevel gear 292 journalled for rotation about a horizontally disposed axis within the spindle head. The 

